Telephones at their inception were relatively large and often unwieldy devices, and necessarily so. Incorporated into a telephone was both a microphone and a speaker, each situated so that it could be employed by a user attempting to engage in conversation, as well as the electrical circuitry needed to drive them. All of these components were almost primitive by modem standards. Typically, the microphone was incorporated into a single component that served as a base and housed most of the circuitry. A speaker attached to the base by a cord could be held up to the user's ear. In other models, the microphone and speaker were incorporated into a single handset, which was attached to the base housing by a cord (this, of course, remains a popular design). The handset disposes a microphone approximately six inches from the speaker so that it is proximate the user's mouth when the speaker is held to the user's ear. The user can therefore turn in any direction and still retain both speaker and microphone in a usable orientation. This manner of speaking on the phone is standard and almost universally recognizable. Nearly anyone in the modem world would, therefore, understand how to use a handset for telephone communication, even if they had never seen a particular telephone instrument. This is generally true notwithstanding the great variation in the cosmetic design of the instrument. For example, a telephone handset may take on the appearance of an automobile or a shoe, in addition to simply being a conventional design. The user would nevertheless determine in short order how to hold the speaker of the device to their ear and speak into the microphone
While a convenient improvement over prior systems, however, the handset nevertheless had the disadvantage of requiring the user to hold it to an ear with a hand or by awkwardly holding it between head and shoulder. Further improvements in microphone and speaker technology have addressed this disadvantage by allowing for the more widespread use of “hands-free” or “speaker” phones. With such instruments, once the call is established, the user does not have to hold or manipulate the phone at all, but simply talks in the direction of the microphone. Improvements in microphone technology will allow the user to be understood by the called party even if speaking at a distance of several feet from the unit itself. By the same token, the speaker is loud enough to be heard at that distance. Obviously, several people may participate in the call without the need to pass a handset back and forth or use a second instrument connected to the same line. A conventional handset is still desirable in certain situations, of course, such as those that require a certain amount of privacy.
While at times this need is still felt, however, phone conversations involving more than one user on each end of the line are becoming increasingly common, especially, but not exclusively, in business settings. At the same time, there is an increased awareness that in certain settings, such as using a mobile or portable phone while driving, watching children, and other activities requiring visual attention, it is safer to use a speakerphone to avoid the relatively reduced mobility arising from having to maintain a telephone handset in a certain position. Even where safety considerations are not of concern, at times users will simply prefer to speak on the telephone while maintaining both hands-free for other tasks. Given all of its advantages, coupled with the advances in technology providing ever-greater sound quality, the hands-free speakerphone is likely to become more and more popular.
A hands-free phone's speaker, which is remote from the user's ear, must be louder, of course, than one on a conventional handset that is held next to the ear. Otherwise, it will not be heard. The volume may be adjustable, but will often be adjusted loud enough to be heard by several parties somewhat separated from the instrument itself. This increased volume does present somewhat of a hazard if accidentally held too close to a user's ear. Such an accident may occur if a user unfamiliar with a specific hands-free phone mistakenly believes it to be a conventional handset or simply picks up the device and holds it to an ear reflexively. Whatever the reason, the user may then experience a sudden loud noise, generated not by a conventional handset speaker, but by the much louder hands-free speakerphone speaker. The effect of such a sudden loud noise emanating from a telecommunications device is sometimes referred to as acoustic shock, and can result in temporary or even permanent hearing damage. Even if not a cause of hearing damage or related injury, however, such a sudden, loud noise so close to the ear is both irritating and uncomfortable. It is an experience most users would wish to avoid.
The risk that a user will too closely position a large speakerphone is not high. Especially when the instrument itself is obviously not intended for handheld use. In other circumstances, however, the risk is greater. The telephone, like other electronic devices, has through improved miniaturization techniques and other advances in technology became increasingly smaller. A speakerphone with a satisfactory microphone and speaker can now be quite compact, approaching the size of a cellular phone. This small size is desirable, of course, because they are more portable, less obtrusive, and easier to mount in an automobile or other such location. The compact nature of these instruments, however, may mislead some users to assume that they are small portable or celluar phones and press the speaker against an ear. This is not an unexpected phenomenon, especially when considered in light of the wide variation in modem telephone design, producing shapes that are not limited to a few widely recognizable models. Needed, therefore, is a way to avoid acoustic shock from confused users placing high volume phones to their ear, while at the same time retaining the design flexibility to offer small and aesthetically pleasing styles.